Method of removing dust from leather



Sept. 27, 1949.

J. ca. HOI LICK METHOD OF REMOVIN DUST FROM LEATHER Filed Au 16, 1946Inventor John a h'olliqk Patented Sept. 27, 1949 METHOD OF REMOVING DUSTFROM LEATHER a I John G. HollickQ Beverly, Mass., assignor:v to UnitedShoe Machinery Corporation, Flemington, N. J., a corporation of NewJersey 7 -Application August 16, 1946, Serial No. 691,090

. 1 This invention relates to a method of removing dust particles from.the surface of tanned hides or skins, and is morespecifically concernedwith the freeing of leather surfaces from 'fine fibrous dust by means ofa forced jet of gaseous fluid such as air. 1,. Tanned hides or skins.are usually subjected to a bufiing operation to improve theirappearance, after which thedust produced by that operation is removedfromv the .leather surface. Such removal is for the. purpose-ofpresenting the leather in the best possible condition for subsequentfinishing operations. If:the dust were not removed, the resultingfinishwouldbe cloudy, streaked andunsightly. g .5 S

Dust, and particularly that dust produced from bufling, is fine andfibrous and great. difiiculties are encountered in satisfactorilyremoving it from leather surfaces. Thev problemsencountered are uniqueand quite unlike those-involved in clean ing other types of sheetmaterials. f

Heretofore it has-been the practice to employ. brushing machines to,remove, dustfrom leather. In using such machinesdust would momentarily.be lifted by the brush from the leather surface. After such mechanicaldislodgment, means would remove some of the dust suspended in the air.As the brushing action led to generation of static charges inthedustparticles and also in the leather there has beena strong tend-; ency forsome of thedislodgeddust to return to the leather despite the suctionmeans. 1 Asa result, the finish and appearances of. the work hassuffered and the difficulties. have not been avoided by the developmentand improvements in complicated brushing machines which are costly tomanufacture and. expensive, tomaintain. It has now been discoveredthatdust may be removed from leathersurfaces, by anair jet to a degree notapproached by the best brushing machines and that the capacity of theair han--v dling equipment may be quite modest. The method is thereforeeconomical and is aidediin this direction by the discovery that thecleaning effect takes placesubstantially instantaneously and that therate of feed of a work piece surface relative to a cleaning jet may begreatly increased as compared with the rate with which leather may bedusted'in a conventional brushing machine. It has also been found thatthe dust dislodged by an airjet or blast may easily be controlled sothat it will not return to the cleaned leather surface. I I

An object of the invention is to provide an my.

suction v T 1 Claim. (01. 69-21) e 2 latter being in the form of a hideor skin, which method is simple, efficient'and economical.

In the accomplishment of the object in View and in accordance with themethod herein illustrated, a forced jet of gaseous fluid such as air isdirected against a narrow area of the surface of a spread-out leatherwork piece to be treated and at an angle such as to cause the jet toimpinge against the surfaceand dislodge dust therefrom. All portionsofthe surface to be treated are progressively passed through the zone ofimpact of the jet. Thus not only is the dust most effectively dislodgedfrom the leather under treatment but thedust laden air, afterimpingement, is forcibly directed away from the cleaned surface as anincident ofthe cleaning operation. The jet, before impingement, is givena limited width dimension "of a few thousandths of an inch.

The invention will now be more particularly described by reference tothe accompanying drawings and thereafter pointed out in the claim.

In thedrawings, l

Fig. 1 is a. perspective view of one form of apparatus by means of whichthe method may be carried out; and 1 a 1 Fig. 2 is a view, in section,and drawn to a larger scale, showing the relation of the main operativeparts of Fig. 1 in treating a leather work piece.

Inthe illustrated machine, a horizontal table or platform I0 is utilizedupon which 'a leather work piece l2 maybe supported and spread out andfrom which it ma y be progressively fed through the treatment zone orzone of impact. Bearing blocks l4 and 'lG are rigidly attached to theopposite sides andat the end of the platform I0 and rotatively supportthe shaft I8 of an elongated rotary brush 20 having sufficient length toextend across and slightly beyond each side of the widest work piece thetreatment of which is contemplated. A vertical bracket 22 is adjustablymounted-and supported upon the bearing block [6 by suitable bolts 24 and26. Each of these bolts passesthrough a vertical slot made in thebracket 22. --A slot 28 is formed in the block it permitting angular:adjustment of the bracket 22 about the bolt 24.' The bearing block I4supports asecond vertical bracket 30 similar in all respects to thebracket: 22 and likewise adjustably mounted. A horizontal bar 32 issupported Lon brackets 22. and 39 by flanges 34 and 36 boltedto theupper endsof the brackets 22 and30.

As seen in Fig. 2,-the barv 32 is formed with a recess 35 runninglongitudinallythereof and enproved method ofrem yinedust from. leather,the. 555 closed by two longitudinal plates 31 and 38. The

recess 35 does not extend the full length of the bar 32 but terminatesadjacent each end thereof. The plate 38 is attached to the bar 32 by amultiplicity of screws 40 one of which is shown in Fig. 2. Thelongitudinal plate 31 extends from one longitudinal side of the bar 32and almost abuts the plate 38 thereby leaving a'slot 42 of slight widthbetween its edge and the inner side of the plate 38. A multiplicity ofcylindrical pins 44 are attached to the bar 32 by means of screws 46(only one shown and that Fig. 2) passing through the plate 31 into thebar 32. The cyline drical bars or pins 44 extend at an angle up over theplatform or table In, as shown in Fig. 2, and are smoothly contoured toguide the work into the bite between the plate 38 and the brush 22.

One end of the bar 32 is provided with piping connections 50 and aconduit 52, these devices serving as means for conducting gaseous fluidsuch as air under positive pressure from a source of supply to therecess 35. A pressure gage 54. is shown in Fig. 1. One end-of the rotarybrush shaft [8 has keyed thereto. a pulley 6.0 through Whichpower isapplied to. the machine by a belt $2 driven from motor means not shown.

In carrying outv the method the pulley 60 and brush 20 are rotated inthe direction shown by the, arrows in Figs. 1 and 2: and air underpressure permitted to enter the hose 52, piping connections 50, and therecess 35. The bar 32 is ad-. iusted to a position such as shown in Fig.2. The operator then places, and spreads out a hide or l2 upon the tablet0. and slides it in between the rods or pins. 44 and the rotating brush20.. Regardless of the irregularities in the contours of the work piecethe brush serves. to progressively pull the work piece 12 by and incontact with the wer ed e of the plate 38. and air, emanating in theform of a sheet, from the slot. 42 betweenthe plates; 31, and; 38,impinges. upon the surface of the spread-out. work piece 12, dislodgingdust therefrom. Before impingement, the thickness dimension of the jetis not. excessively increased as the work piece is retained close up to.the slot As preferred and as disclosed in the apparatus shown, thedustrladcn air then sweeps back over that. or ion. o he work piece surfae n t y cleanedand the treated; portion 64. of the work piece surfaceemerges, from the machine freed ir mcl st.

The op rator m y ho d a k; on a hide or skin and retard its passage if;he so desires and, as a matter of fact. he may pull; the work piece backtoward him then permit it. to be treated again by the jet. Usually one.passage of a. portion of a r pi ce past he slotor through the zone ompac ssniiicientto remove the dust but. it is; obvious that the operatormay Without Iemmling' the work; from the machine, repeat the treatmentof a given work piece any number of times, or he may prolong thetreatment during a single pas-. sageby retarding the. rate of feed.

A hood; for the removal. of the dust-laden air, is not essentialessential. as the blast of air from the slot removes the dust such adistance that it does not return. to the leather. It is preferable thatthe method be so carried out-that the dustladen air flies back overtheleather portions yetto be fed. by the slot. With the apparatus shown,the. plate. 38: and the bar 32- prevent dust-laden; air from flying outover thedusted portion- 64 of the leather. It is to be appreciated,however, that a. hood may be used to'insure'that all dust is removedfrom the leather and will not return thereto.

An air pressure of from three to twelve pounds per square inch withinthe recess has been found very satisfactory with a slot width of from.002" to .003. A pressure of three pounds per square inch performed workequivalent to that performed on the best brushing machines. The use of atwelve-pound pressure resulted in a far superior cleaning job. r

It is preferred that the air be impinged against the Work from a slotbut it is clear that a number of closely arranged or staggered orificesof small thickness dimensions may be used and that these may constitutethe cleaning jet. It is also permissible to reciprocate the slotted orperforated jet member to secure adequate coverage of the surface area tobe treated. In some cases it may be well to increase the width dimensionof the orifices or slots to as much as .015" or .020 although suchincrease will necessitate a great increase in the capacity of the blowerand the power output. I

Various. velocities of feed for the work piece have been foundsatisfactory. The cleaning effect is substantially instantaneous. forany given spot on a. work piece: despite the small width of the slot andcleaning jet as work-feed velocities of up to 325 feet. per minute havebeen successfully used.

The specific apparatus. disclosed includes the rotary brush 20 forfeeding the work piece resiliently in contactwith. or closely adjacentto the plate 38.. As the dust-laden air discharges, the Bernoulli effectis evident potentialenergy is changed to kinetic energy and the pressureof the air within the jet is reduced and the leather is actually held(not repelled) adjacent to the slot 42 by the air jet. A rotary brushneed not be used for feeding the work piece as that operation mayobviously be carried out by hand or by a belt conveyor;

It may be seen from the above that the velocity of feed and the pressureof the fluid used are not. critical conditions in so far as theinvention is concerned. The impingement or impact angle of the jet(asmeasured with respect to the surface being treated and beforeimpingement) should not be much.- lower than degrees (although the40-.d'egree value is not critical) if the advantageous results are tobesecured. The impingement angle of the jet has been found mostsatisfactory when approximately 90 degrees and the cleaning effectdiminishes if the angle-is adjusted or changedtoapproach zero.

It is preferred thatthe method be carried out as disclosed in Fig. 2 butit'is not essential that the dust-laden air be discharged over theuntreated portion ofthe work piece. The dustladen air maybe dischargedin the other direction-.-i. e., over the treated work portion 6&-

and be separated therefromby a thin plate or sheet and/or by causing thework piece to bend sharply away from the direction of movement of thedust-laden air;

Having described my invention, what I claim as new and desire-to'secureby Letters Patent of the United States is:

A method: of removing dust from leather'which comprises the spreadingout of a work piece such as a hide-or skin upon a support andpassingsaid work piece progressively through a zone of treatment, andforcibly projecting a jet of air undera pressure of substantially threeto twelve pounds per square inch directly against and also across thefull width'of the work piece to treat the entire length of" said workplece-asit passes through said zone, the impingement angle of the jetbeing above 40 degrees and the thickness dimension of said jet beforeimpact being within the range of .002" to .020".

JOHN G. HOLLICK.

REFERENCES CITED The following references are of record in the flle ofthis patent:

Number 6 UNITED STATES PATENTS Name Date Scharrer May 5, 1896 ThurmanMar. 25, 1902 Thurman Apr. 14, 1903 Thurman Nov. 17, 1903 Hubbard Feb.21, 1922 Bagshaw Oct. 7, 1941

